Method of measuring the rate of flow of liquid



'Feb. 8,-1927.

I 1,616,481 C. M. x 7

METHOD OF MEASURING THE RATE OF FLOW CF'LIQUID Original Filed Oct. 2, 1922 @1 1. 3' Kw g Patented Feb. 8, 1927..

UNITED STATES cnAnLEs m. ALLEN, or WORCESTER, :wmssacmrsncr'rs.-

METHOD Application filed October 2, 1922i Serial No. 531.997.

This invention relates to a method of measuring the time which a liquid takes in passing from one point to another through a pipe, penstock, or the like of constant or varying cross sections'so that the rate of can be used'universally even where the water held in solution therein.

g which the oscillations are w cannot be seen and which will be accurate, reliable, and, simple.

Reference is to be ing drawing which is a diagrammatic view of a penstock showing .how this method can be carried out in connection therewith.

,\ This method depends upon the fact that the electrical conductivity of a liquid is changed by certain chemicals which may be It consists briefly in introducing into the pipe or other conductor a .salt or other soluble compound which will affect the electrical conductivity of the liquid and had to the accompanyobservlng the time of 1ntroduction of the compound, of initial appearance, maximum density and final appearance thereof. One way to do this is to measure the current that passes between two electrodes introduced into the pipe, or to measure the voltage or resistance.

In-theform shown, the flow of water is 'being measured in a large steel penstock 13 ,of constant or variable section; At the upper end of the pen'st ock, which can be taken as a starting point in some cases, acting valve 10 is located in it. This is shown as placed in horizontal position facing downstream at the center of the pena quic stock 13 at its end and in the plane of the entrance. The solution is piped to this valve from a tank 15 elevated to give any desire head or a pressure tank can be used. In the tank is placed a solution of a soluble salt or compound which will affect the conductivityof the water as vforexample common salt.

handle-16 and pre it may be held 0 of time.

At a measured distance from the,valve 10 downstream is placed a pairof electrodes The quick acting lZilve can be operated by a.

for any desired length 20. One of these is connected through a switch 21'with an electrical measuring 1nstrumentj22, as for .example an ammeter which is connected to the other-side of the line. This-a-rnmeter shouldbe' of a type'in 10, i and the other ing inst ument.

erably is arranged so that PATs ro -Fi OF MEASURING- THIi RATE OF FLOW OF LIQUID.

Renewed December 16, 192 6.

the size and distance apart of the electrodes.

Telephonic or other instantaneous communication is established between two ob servers, one at the point at which the salt solution is introduced, that is, at the valve at the ammeter. Stop watches can be employed to determine the time of the first appearance of achange in the electrical conductivityof the water, time of maximum density and time of disappearance. This .is an example of one wayto carry out the method. The voltage or resistance can be measured instead of the currentor the observations can be made in any scientific way, for example by recording instruments. If the rate of flow has to be measured between two points along thepipe or penstock both at a distance from the point at which the solution can be introduced a second pair or sets ofpairs of electrodes 30 will be employed. Then the time of flow from the electrodes 20 to the electrodes 30 is found in the same way by the use of a second ammeter 32 or other measur- In operation, the soluble compound, as

for example salt, in solution in the tank, is

introduced into the penstock or pipe 13 by opening the valve 10. At the instant this valve is opened and closed-signals by telek phone or otherwise are given to the observer at the ammeter and the stop watches are started. He observes the ammeter and notes the time of initial appearance of increased conductivity that results in a larger current, also the time of maximum density or cond ductivity and disappearance of the solution.

-I- find in practice that the time of initial appearance of increased current and the time of maximum current are definite and reliable but that the time of disappearance of the change is indeterminate and thereforethe mean time which involves that isunreliable. Comparison of tests made in this way with those conducted with a weir, weigh'ng tank, or standard measuring device, shows that the elapsed time between, introduction and maximum density'of solutionor elapsed time between the time of maximum density at one station and that at another can be accurately determined. The time elapsed as stated above appears to give the correct time 11 damped and independent of the length or, variation in diameter and internal condition of the pipe and it is directly proportional to the'volume included between the two stations for a given rate of flow. Having determined the elapsed time by this method therate of flow is found by the well known .formulaRate cu. ft, er' sec.=v0lume divided -,by time.

' fReasona 1e variations in the strength of charge of the solution, the length of charge, the amount of deflectionof the instrument, size and'cle'arance of the electrodes do not affect materially the accuracy of the results. I have also compared the result of this method with the so-called color method in which a soluble color is used to measure the frate of flow and which is limited to cases in which the'water can be seen and 'I find that the accuracy of the present method is that the invention is "capable of being carried out .independent of the particular apparatus illustrated, and that it can be per formed accurately with any soluble compound that affects the electrical conductivity of the liquid in accordance with the claim.

Having described my invention, what I claim is I y The method of measuring the rate of flow of water 'in a conductor, which method consists in introducing into the water flowing freely in' the conductor a soluble substance which locally alters the electrical conductivity of the water; measuring the resulting changes produced by the solution inan elec immersed in the water and constituting parts of an energized circuit and'similarly measuring the changes in current passing between 'tric current passing between two electrodes 9 two electrodes constituting parts of another energized circuit'as the solution passes another point at which the second electrodes are located, the location of. which second pair of electrodes with reference to the first pair'being such as to include between them a known volume of water, and-m asuring? the elapsed time between the moments o corresponding changes in electric currents between the .two pairsof ele trodes.

In testimony whereof aflixed my ,s ignature.--

' 5 "-CH',.\I.tLES-M. ALLEN.

1 I have hereunto 

